Q: Which of the following equations correctly represents the hydrolysis of ATP by myosin ATPase during muscle contraction?

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P_i} + \text{energy}$$

Question 1

Which of the following proteins is directly responsible for hydrolyzing ATP during skeletal muscle contraction?

Accepted Answer

Myosin ATPase

Question 2

A sprinter is running a 100-meter dash. Which muscle fiber type is primarily recruited for this explosive activity?

Accepted Answer

Type IIx (fast-twitch glycolytic)

Question 3

Which of the following best describes the role of myoglobin in skeletal muscle?

Accepted Answer

It binds and transports oxygen within muscle cells.

Question 4

During a biceps curl, as you slowly lower the weight back down, which type of contraction is occurring in the biceps brachii?

Accepted Answer

Eccentric isotonic contraction

Question 5

Which energy system provides the fastest supply of ATP for muscle contraction but is depleted within seconds?

Accepted Answer

Phosphocreatine system

Question 6

A patient experiences muscle weakness after prolonged exercise. Laboratory tests show normal CNS function but decreased muscle force. Which type of fatigue is most likely present?

Accepted Answer

Peripheral fatigue

Question 7

Which of the following best describes wave summation in skeletal muscle?

Accepted Answer

A second stimulus applied before the muscle fully relaxes, resulting in a stronger contraction

Question 8

What is the correct order of motor unit recruitment during increasing muscle force?

Accepted Answer

Type I → Type IIa → Type IIx

Question 9

Which of the following statements about isometric contractions is TRUE?

Accepted Answer

The muscle generates force without changing length.

Question 10

A muscle is stimulated at a frequency that does not allow complete relaxation between twitches, resulting in a sustained but wavering contraction. What is this phenomenon called?

Accepted Answer

Incomplete (unfused) tetanus

Question 11

Which of the following best explains the function of series elastic elements (SEEs) in muscle contraction?

Accepted Answer

They transmit force and absorb slack during isometric contractions.

Question 12

Which muscle fiber type is most resistant to fatigue and is primarily used for maintaining posture?

Accepted Answer

Type I (slow oxidative)

Question 13

Which process is responsible for restoring sodium and potassium ion gradients after an action potential in skeletal muscle?

Accepted Answer

Na+/K+ ATPase

Question 14

A weightlifter holds a heavy barbell stationary above their head without moving it. Which type of muscle contraction is occurring?

Accepted Answer

Isometric

Question 15

Which of the following is a characteristic of fast-twitch glycolytic (Type IIx) muscle fibers?

Accepted Answer

Large diameter and rapid force generation

Question 16

Which scenario best illustrates asynchronous recruitment?

Accepted Answer

Motor units alternate activation to delay fatigue during prolonged activity.

Question 17

Which of the following equations correctly represents the hydrolysis of ATP by myosin ATPase during muscle contraction?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P_i} + 	ext{energy}$$

Question 18

Which of the following best describes the difference between concentric and eccentric isotonic contractions?

Accepted Answer

Concentric contractions shorten the muscle, eccentric contractions lengthen it under tension.

Question 19

A marathon runner relies primarily on which ATP-generating pathway during the majority of the race?

Accepted Answer

Aerobic respiration (oxidative phosphorylation)

Question 20

Which of the following best defines a motor unit?

Accepted Answer

A single motor neuron and all the muscle fibers it innervates

Whole Muscle Physiology: Skeletal Muscle Contraction and Mechanics

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